KeyGhost

Turn Caps Lock into a launcher. Hold the key, see your apps, press a letter to launch.

KeyGhost is a macOS menu-bar app that turns any key — Caps Lock, F-keys, even Right Option — into a launcher. Hold the trigger and a translucent keyboard fades in showing the app icon bound to each letter. Press a bound letter while held and the app launches immediately; the chord is consumed so it never reaches your focused window. It reads the trigger key from the HID layer, beneath any modifier remapping, so it works regardless of Hyperkey, Karabiner, or macOS Modifier Keys.


Try it here

Caps Hold to summon the overlay. Then press T, M, C, S, or B to launch. Try F + // for the radial menu.

Finder File Edit View Window Help 21:45
main.swift — KeyGhost
func launch(_ binding: Binding) {
  NSWorkspace.shared.openApplication(
    at: binding.url, configuration: .init()
  )
}
Notes
Things I keep reaching for the mouse to open…

— Chrome (current tab? new tab?)
— Terminal in the right cwd
— Calendar for today's standup
Click here, then hold Space or press & hold Caps above

In the real app the trigger is Caps Lock (configurable). Browsers can't intercept Caps Lock, so the demo uses Space instead. See it on a real keyboard.


What makes it different

🔑

HID-layer trigger detection

KeyGhost watches the raw HID usage code for your trigger key — below Hyperkey, Karabiner, and macOS Modifier Keys. Use Caps Lock as a launcher and as Hyper at the same time.

🧭

Nested radial menus

Bind a letter to a root action, plus four arrow-direction sub-actions. Caps + F opens Chrome; Caps + F + ↑ opens Gmail; Caps + F + → opens Calendar. One key, five destinations.

🔁

Passthrough mode

Some keys you want to forward, not consume. Mark a binding as passthrough and KeyGhost rewrites the event flags to the full ⌃⌥⇧⌘ chord before letting it through — perfect for Maccy, Raycast, or Shortcuts.app hotkeys.

🖥

Live cheatsheet

A translucent keyboard overlay fades in after the configurable hold delay. App icons resolve live from NSWorkspace so they always match what's installed on your machine.

Click-to-edit settings

Open Settings, click any letter on the on-screen keyboard, pick an app or URL. Or edit ~/Library/Application Support/KeyGhost/bindings.json directly — the file is live-watched.

📡

Sparkle auto-updates

Signed & notarised builds, EdDSA-signed appcast served from Cloudflare R2. New versions land via the menu bar's "Check for Updates" — no App Store, no subscriptions.

📝

Any trigger key

Not just Caps Lock. Pick F13–F20, Right Option, either Shift, or any other modifier — KeyGhost captures the HID usage code so it works regardless of any user-space remap layered on top.

💨

Tiny & native

Pure Swift, SwiftUI overlay, CGEventTap chord detection. No Electron, no helper daemons. Lives in the menu bar and stays out of your way.

📖

Open source, MIT

Build from source with swift run. Ship your own signed build with one script. Or just download the signed DMG and go.


How it works

1. HID detects the trigger

TriggerKeyMonitor opens an IOHIDManager on the keyboard usage page and watches press/release of your trigger key's HID usage code (e.g. 0x39 for Caps Lock). Below any remapping layer.

2. Overlay fades in

If the trigger is still held after holdDelayMs (default 250 ms), a borderless SwiftUI panel fades in over your current window, showing the keyboard grid with live app icons.

3. Chord is intercepted

ChordMonitor runs a consuming CGEventTap. While the trigger is down and a bound letter is pressed, the event is dispatched to the launcher and swallowed before reaching your focused window.

4. App launches

NSWorkspace.openApplication(at:configuration:) opens the app, or NSWorkspace.open([url],…) opens a URL in a specific app (Gmail in Chrome, GitHub in Arc, …).


Get started

Download the signed DMG, drag KeyGhost.app to /Applications, and launch it. You'll grant Accessibility and Input Monitoring on first run, then add bindings from the menu bar's Settings panel.

Download latest release

Or build from source

# Requires Xcode 15+ (Swift 5.9, macOS 14 SDK)
git clone https://github.com/3stacks/keyghost.git
cd keyghost

# Debug build, run in place
swift run

# Release .app at build/KeyGhost.app
./scripts/build-app.sh

# Signed + notarised DMG (needs SIGNING_IDENTITY)
./scripts/build-dmg.sh

See the README for bindings format, nested radial syntax, and release tooling.